Conservation of standing structures

The Ancient Merv Archaeological Park encompasses archaeological
sites of the last four thousand years during which the main building
material has been earth: sometimes made into mud bricks and bonded
with mud mortar, sometimes rammed or placed into position, and
nearly always covered with mud plaster.

The architecture and archaeology preserved in the Park is of international
importance, partly due to the preservation of standing structures,
such as the corrugated Kyz Kalas and the spectacular icehouses,
and also because of the excellent preservation of over 1,000 hectares
of buried archaeological deposits.

The east face of the Little Kyz Kala in 1954.

The same face of the Little Kyz Kala in 2003 shows
how much erosion has taken place. The erosion is mainly caused
by the wind.

Threats to the site

For over two thousand years the main building material in Central
Asia has been earth: sometimes made into mud bricks, sometimes
rammed or placed into position, and nearly always covered with
mud plaster (a mix of mud and straw). As people building in earth
today know, such buildings need regular maintenance, with new
coats of plaster applied to walls and roofs every few years.

Once the buildings and town walls at Merv were abandoned the
process of decay started. Wind and rain steadily eroded
the structures:
once roofs had collapsed, walls lost material from both their
tops and faces. However, the process was gradual, so buildings
like
the Great Kyz Kala have only lost about 1.5m in height over
a thousand years.

In recent years, however, the process has accelerated considerably.
The watertable in the Merv Oasis has risen due to the construction
of the Karakum Canal. While this has brought major advantages
for the agriculture of the region, it has been disastrous
for the standing
buildings. Water seeps into the bottom of the walls, and
as this dries the salts in the water crystallise on the
wall surface.
This
makes the surface much more fragile, and the wind removes
the face of the wall rapidly. The result is great portions
of the
wall base
collapse, and this process happens annually until the whole
wall falls down.

Today the damage to the surviving earthen architecture and
archaeology at Merv is accelerating. The main problems
are:Water (a)
rising groundwater - water seeps into the bottom of the walls,
and as this dries the salts in the water crystallise on the wall
surface, eroding the base of wall (undercutting).
(b) falling water - in the form of rain or snow damages earth buildings
and makes the surface much more fragile.

Wind.
Wind removes the faces of walls. Wind can carry desert sand
and this blasts and abrades the walls.

Vegetation.
Plant roots can grow through and damage the earth walls and
buried archaeology. Plants can also trap moisture, and lower
the relative
temperature, which can speed up damage to the fragile earth
structures.

Animals.
Humans move out and animals, birds, insects, and reptiles move
in to earthen buildings. Animals can excavate burrows in
earthen material, and by depositing their waste they can accelerate
the rates of erosion.

People.
Sometimes the people who come to visit the monuments in the
park cause damage to them. This is because taking the same
path through
a monument can cause it to erode. In addition the park
and the monuments are sometimes damaged by illicit activities
such as
robbing.

Conservation and Management Solutions for the Site

To find the best solutions for Merv we are undertaking
experiments with traditional materials, such as mud plasters,
mud mortars
and mud bricks, as well as new materials, such as using
a geotextile to separate the new conservation work from
the
archaeology.
We are also using techniques that have been developed
on other sites
around the world, such as backfilling, alongside techniques
more local to Merv, such as including wheat straw in
mud plasters. We
hope that by combining new and traditional techniques,
with information
from around the world, and from Merv, that we will find
the best solutions for conserving these fragile earth
structures.

During
past fieldwork we undertook an evaluation of all the standing
historic structures and extant archaeological
trenches
within
the Archaeological Park, assessing their current
condition, research and educational potential, and conservation
priorities. This
has
been instrumental in shaping an emergency conservation
programme for the Park, which is now underway. Some
of the work we have undertaken so far
includes:

STANDING
BUILDINGS:

• Repairing
eroded wall bases. The heavily eroded and undercut
wall bases have been filled and packed with new mudbricks.
These repairs provide
support for the structure and limit the effects of damage from rising water,
as
the erosion occurs in the new material rather than
the old material. In some places underground drains have been installed,
and in other the original fired brick damp-proof course has been reinstated.

• Drainage
works. Conservation work has been carried
out to give the monuments better drainage. Simple measures
like building low slopes
are effective in redirecting water run-off from particularly fragile areas
in monuments.

• Capping. Work
at the top of walls is carried out to help water flow away from
the
structure. This is through placing new mudbricks or new
plaster of the tops of walls. This ‘cap’ makes rain
or snow fall away from the wall or structure and means the erosion
occurs in the new material rather than the old material.

• Preparing
damaged surfaces. Mud plaster surfaces that are damaged and cracked have been replastered
using mud plaster and chopped wheat straw. These surfaces are regularly
maintained to cover cracks and ensure they last longer.

• Replacing
earlier conservation work. Some
earlier conservation replaced the mud plaster finishes and surfaces
on
the monuments with heavier materials, such as concrete
or cement. These harder materials were thought to last longer than
the traditional finishes and surfaces. However they actually caused
more problems, because they were heavier than the original materials
and because these materials stopped the earth structure from being
able to ‘breathe’. As the buildings could no longer
breath moisture could become trapped underneath the cement finish
or surface. Where
it has been possible, such as on the roof of Ibn Zeid, these harder
materials have been removed, and they have
been replaced
with traditional mud plaster.
These enable the building to ‘breath’ again, and with the regular
maintenance of these surfaces the building can last much longer.

ARCHAEOLOGICAL TRENCHES

• Documentation
and Backfilling.
Archaeological excavations over the last 100 years have created
a lot of open and eroding trenches in the archaeological park.
These open and eroding trenches cause problems because they are
big and deep, water runs off in to them. As they are cooler and
attract water, vegetation, animals and birds live in the trenches,
causing damage through burrowing and by depositing their waste.
Because some of these trenches have been left open and eroding
for such a long-time water, wind, plants and animals have caused
the sides of the trenches to slump and have covered what remained
of the exposed archaeology. To try to limit some of the damage
that occurs to the trenches some of them have been backfilled.

Tamping down backfill material in Shariyar
Ark to conserve the archaeological remains. In the background
is ‘geo-textile’ which
covers the walls and allows them to ‘breathe’ through
the backfill.

Recent
Progress

Remedial
work has begun. The Archaeological Park has started to tackle
the
situation with a programme of cleaning and repair, along
with the targeted repairs to support the most vulnerable structures.
A team from CRATerre-EAG in
Grenoble, under the direction of Sébastien
Moriset and with UNESCO support, have constructed a laboratory
for the Park, to explore the chemical properties of the soils and
the best methods for developing sustainable new mudbrick and earth
materials with which to repair and consolidate the structures. The
World Monuments Fund , with support from The
J.M. Kaplan Fund, Inc and the American
Express Company,
have generously supported the Turkmen/UCL/
CraTerre-EAG team, which has enabled a programme of “at risk” emergency
repairs to the buildings within the Park. We have also undertaken
a survey of the canal and irrigation systems, which has been
used to develop a programme of targeted cleaning and repair,
working
with the local community to avoid some of the worst of the seasonal
flood damage.

A further important part of this conservation programme has
been the careful recording, by members of the archaeological
team, of
the areas to be conserved prior to the work beginning. In most
cases this has involved photographic recording, but in certain
cases excavation has been required. What is heartening is the
way that the archaeologists, the conservators and the Park
managers
are working closely together to provide an integrated approach
to these complex problems.

Training programme
A three week training
programme was undertaken at Ancient Merv
Archaeological Park, between the 13th - 30th June, 2005. This
consisted of two courses:
• Course 1: Ethics, philosophy and approaches to the management of
Cultural Heritage sites. A one-week course aimed at a broad audience
from a range of Parks across Turkmenistan. Because of the practicalities
of Park staff availability, this was arranged as the middle week
of the programme.
• Course 2: Approaches to documentation of Cultural Heritage sites.
A two week course primarily aimed at the Merv Park Staff, but also
attended by some staff from other Parks. Practical elements of
the course included:
- documentation and condition assessment of Porsy Köshk;
- documentation of the conservation activities at Erk Kala;
- reburial of archaeological site.

Other conservation activities
Other conservation and management activities undertaken by June
2005 included:
a) Development of a new site management plan for the World Heritage
Site –additional sections have been drafted for consultation
in autumn 2005.
b) Reports have been prepared on the scale and speed of change
of the modern cemeteries in the northern and southern suburbs of
Sultan Kala. This information will enable the Ministry and Park
to open dialogue with the local authority, and community and religious
groups, in the hope of finding a solution to this encroachment
and destruction, while maintaining the social, religious and associative
values of the cemeteries.
c) Development of a glossary of conservation and architectural
terms in Turkmen & English.
d) Translation of existing project documentation and databases
into Turkmen - in progress.
e) Translation of archaeological recording manual into Turkmen
- in progress.

Future Work

The solutions to the conservation problems at Merv are not easy.
It is our challenge to assess the problems and successes of the
work we are carrying out and to build upon the existing knowledge
as a means to help manage this unique site.

At
Merv we are working closely between conservators and archaeologists,
in particular in collaboration with Dr Kakamurad Kurbansakhatov
(The State Institute of Cultural History of the Peoples of
Turkmenistan, Central Asia and the East), Dr Mukhammed
Mamedov and Dr Ruslan
Muradov of the National Department for the Protection, Study
and Restoration of Historical and Cultural Monuments, Ministry
of Culture of Turkmenistan,
and Rejeb Dzaparov, Director of the ‘Ancient Merv’ Archaeological
Park, and Sébastien Moriset and Mahmoud Bendikir CRATerre-EAG (Grenoble,
France). To see our generous sponsors who supported this work
click here.